Pen



FIG. 1 is a front elevational view of the pen;

FIG. 2 is a rear elevational view of the pen;

FIG. 3 is a left side elevational view of the pen;

FIG. 4 is a right side elevational view of the pen;

FIG. 5 is a top plan view of the pen;

FIG. 6 is a bottom plan view of the pen; and,

FIG. 7 is an exploded view of the pen. 

CLAIM The ornamental design for a pen, as shown and described. 